You probably would fail in the "no legitimate interest" and "bad faith registration" criteria, should Microsoft decides to udrp you.
You are most likely going to be challenged as to why on earth you would register an obscure domain name like Windows10. You are not in the house window business. It would be very hard for you to deny that you did not know beforehand that there is a Windows 8 and it is "iterating" in numbers, since Windows is a globally recognized brand.
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Even if there is no such thing as Microsoft, that domain by itself sucks big time. It's much better to drop it.